Evaporator of sheets of different materials



July 39, 19350 J A E 2,099,746

EVAPORATOR OF SHEETS OF DIFFERENT MATERIALS Filed Jan. 12, 1955 {HI/ma: mm I ill/NIH MM F'WQJ.

WITNESSES: 4 INVENTOR [601 m z, JUL.E&N.5RLER Patented Jul 30, 1935 2,009,746

UNITED STATES PATENT OFFICE EVAPORATOR OF SHEETS OF DIFFERENT 'MATERIALS Jules N. Saler, Springfield, Mass., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 12, 1935, Serial No. 1,484

6 Claims. (Cl. 62-426) My invention relates to evaporators for methrough an outlet 24 preferably connecting with chanical refrigerators and particularly to evapthe cross header 22. orators fabricated from sheet metal and it has The inner metal sheet I4 and the outer metal for an object to provide an evaporator of this sheet l5 are preferably secured to each other 5 type which has better operating characteristics by some process such as welding or brazing in 5 and is better constructed than those heretofore order to form a single, autogenous evaporator provided. I structure. In the present embodiment, I prefer This and other objects are effected by my into secure the sheets to each other by are weldvention, as will be apparent from the following ing, in which case the boundaries or marginal description and claims taken in accordance with portions 25 are secured to each other by a con- 10 the accompanying drawing, forming a part of tinuous weld while additional welds 26 are 10- this application, in which: cated between the corrugations l6.

Fig. 1 is a view, in elevation, of a refrigerator Disposed within the sharp freezing chamber equipped with one form of evaporator constructl8 are suitable ice tray supports 21 upon which ed in accordance with my invention; are located ice trays 28 for containing water or 15 Fig. 2 is a section taken on the line 11-11 of other substances to be congealed. Ice trays are Fig. 3 showing the trays in elevation; and also located on the horizontal surface of the Fig. 3 is a view, partly in side elevation and inner evaporator sheet I4. partly in section, of the evaporator shown in In operation, the evaporator absorbs heat from Figs. 1 and 2. the refrigerator cabinet through its outer sheet 20 Referring now to Fig. 1, I show a refrigerator l5 and absorbs heat from, the sharp freezing cabinet I0 embodying an upper machinery comchamber through the inner sheet H. The vapor partment H and a lower food storage compartgenerated inthe evaporator incident to the abment l2. Disposed within the food storage com.- sorption of heat is withdrawn through the conpartment I2 is an evaporator l3 of the sheet duit 24 while make-up refrigerant liquid is sup- 25 metal type. plied through the conduit 23.

Referring now to Figs. 2 and 3, the evaporator Evaporators of this character must, of necesli'comprises, essentially, an inner sheet of metal sity, perform two functions, first, absorb heat I and outer sheet of metal I5. The outer sheet through the outer metal sheet from the refriger- I5 is preferably corrugated, as at It, to provide ator cabinet so as to maintain the latter at a 30 suitable channel spaces I! for containing re-' refrigerated temperature above freezing, such as, frigerant fluid. The inner and outer metal sheets for example, 45 F., and secondly, absorb heat l4 and ii are usually bent, such as shown parthrough the inner metal sheet from the sharp ticularly in Fig. 2, to a substantially U-shaped freezing chamber so as to maintain the latter at a formation to form an internal space l8 generally sub-freezing temperature in order that ice may be 35 referred to as a sharp freezing chamber. The formed in the ice trays and, when formed, mainupper ends of each of the sheet metal sheets tained. have complemental, semi-cylindrical header por- Heretofore, it has been customary, in fabricattions l9 stamped therein and extending longituing evaporators of the type such as shown in 40 dinally to form headers 2|, communicating free- Figs. 2 and 3, to employ inner and outer sheets 40 ly with the upper ends of the channel spaces l4 and H: of the same kind of metal so that, con-. H. A suitable cross header 22 may be provided, sequently, the inner and outer evaporator sheets which cross header extends transversely between have the same coeificient of heat conductivity. the longitudinal headers 2| and communicates Some evaporatorshave employed stainless steel therewith. for both the inner and outer sheets. Others have 45 Refrigerant liquid to be evaporated is supplied employed carbon steel 'or silicon bronze or brass to the lower portion of the evaporator through a for both the inner and. outer sheets. liquid supply conduit 23, which extends through I have, however, conceived the idea of employone of the headers 2| and one of the channel. ing metals of relatively different heat conducspaces H to a longitudinally-extending distribtivities, respectively, for the inner and outer 50 uting header 2!! stamped in the outer sheet I5 sheets. For example, I may employ a metal of and freely communicating with the respective relatively high heat conductivity, such as brass, channel space H. Refrigerant vapor generated for the inner sheet l4 and a metal of relatively low in the evaporator by the absorption of heat heat conductivity such as, for example,.silicon through the inner and outer sheets is removed bronze for the outer metal sheet I. I have 55 found that, by employing different metals such as suggested, arc welding of the two sheets to each other at the numerous places required, is greatly facilitated and, at the same time, a stronger weld is produced. The performance of the evaporator is also improved because there is minimum resistance to the fiow of heat from the ice trays through the inner sheet M to the refrigerant fluid while there is relatively greater resistance to the flow of heat from the refrigerator cabinet through the outer wrapper sheet 15. As a result of this difference in conductivities, the single temperature of the refrigerant contained in the evaporator can better maintain the relatively different temperatures required in the food compartment and in the quick freezing chamber.

In addition to the specific materials mentioned, it is within the purview of my invention to employ stainless steel, Monel metal or nickel silver alloys for the outside sheet and to employ, for the inner sheet, a metal of relatively higher thermal conductivity such as, for example, carbon steel. Then again, I may employ similar metals for both the inner and outer sheets but obtain equivalent results by coating the outer sheet with a material such as, for example, rubber or enamel while conserving the thermal conductivity of the inner sheet in order that the thermal conductivity of the outer sheet may be less than that of the inner sheet.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are set forth in the appended claims.

What I claim is:

1. Heat-absorbing apparatus for a refrigerator embodying two sheets of metal secured to each other and forming a chamber for refrigerant liquid to be vaporized, one of said sheets of metal having a relatively higher thermal conductivity than the other sheet.

2. Heat-absorbing apparatus for a refrigerator embodying an inner sheet and an outer sheet havingportions secured to each other, said inner sheet forming a freezing chamber and said outer sheet forming, with the inner sheet, a chamber for refrigerant liquid to be vaporized, said inner sheet having a relatively higher thermal conductivity than the outer sheet. v 3. Heat-absorbing apparatus, as claimed in claim 2, wherein the inner sheet is composed of brass and the outer sheet is composed of bronze.

4. Apparatus for absorbing heat from a refrigerator cabinet embodying two, nested, sheet metal shells having portions autogenously secured to each other and other portions spaced from each other so as to form a chamber for refrigerant liquid to be vaporized, said inner shell defining a freezing chamber and said inner shell having a higher thermal conductivity than the outer shell.

5. A heat-absorbing unit for refrigerating apparatus comprising a sheet metal casing so arranged as to form a freezing compartment for the reception of articles to be frozen, a second sheet metal casing disposed around the first casing and having a portion of its surface in contact with the first casing and having the remaining portion of its surface spaced therefrom, means for securing one of said casings at its periphery to the other of said casings to provide a closed chamber for containing refrigerant fluid, and means for securing the casings to each other at intermediate contacting portions, said first and second casings being composed of relatively different metals and said first casing having a relatively higher thermal conductivity than said second casing.

6. In a heat-absorbing element for a refrigerator cabinet, the combination of spaced sheet metal members having a heat-absorbing fluid circulating therebetween, means located on one side of said spaced members for congealing liquids and means located on the opposite side of said spaced members for storing foods, the sheet metal member adjacent the liquid congealing means having a relatively higher heat conductivity than the sheet metal member adjacent the food storage means.

JULES N. SALER. 

